Bags for packaging drugs require properties such as flexibility enabling easy shrinkage, transparency enabling easy observation of a use state of solutions, heat resistance to endure sterilization at a high temperature, heat sealability, drop impact resistance and drug stability.
Polyvinyl chloride has been the most generally used material for pouches to package medical solutions, and has sufficient flexibility, thus exhibiting superior properties such as transparency, heat resistance, modulus and impact resistance, required for bag molding. However, compounds such as DEHP, plasticizers added to secure these properties are harmful to humans and polyvinyl chloride is also harmful to the environment, thus being unsuitable for use. Techniques to provide alternatives to these substances are disclosed in Korean Patent Application No. 2000-32659 entitled “medical multilayer film”, while the present invention provides a resin composition for films with superior cold resistance and impact resistance.
In general, medical containers to package drug solutions are sterilized by heating at about 121° C. for about 20 minutes or longer. The medical container, in particular, a film outer layer, should have heat resistance to endure high temperatures when exposed to hot water vapor in the heat-sterilization process. In addition, the film may break, thus being unsuitable for use, when medical containers are allowed to stand at a low temperature and impact is then applied thereto. Accordingly, there is an increasing need for development of films suitable for medical containers which can endure heat sterilization (that is, they have heat resistance) and are not readily broken at low temperatures (that is, they have cold resistance and impact resistance).
Patents associated with infusion solution containers among medical containers such as Korean Patent No. 10-0275989, Korean Patent Laid-open No. 2004-0086373, U.S. Pat. Nos. 6,017,598 and 6,007,529, and Japanese Patent Nos. 1994-286087 and 2001-226499) disclose monolayer or multilayer films or containers, each containing an inner layer made of an alpha-olefin or styrene polymer.
The infusion solution container may have any one selected from a variety of shapes and, in a representative structure thereof, the infusion solution container includes an inner bag and an outer bag which surrounds the inner bag to protect the same and serves as a gas barrier to block permeation of gas such as oxygen. The infusion solution container may be selected from functional bags for infusion solutions including a plurality of (two or more) chambers and general flexible plastic containers for infusion solutions including one chamber. However, as compared to the functional bag for infusion solutions including the plurality of chambers, the general flexible plastic container for infusion solutions including one chamber exhibits easy peeling in which an inner sealing layer thereof can be readily peeled and secures cost-competitiveness through use of optimally priced materials. Flexible containers containing infusion solutions may break during transport.
In particular, when a great amount of solutions are packaged together to reduce transport costs, breakage may more readily occur. To prevent loss caused by breakage, sufficient drop impact resistance and low-temperature impact resistance enabling storage and utilization even at low temperatures in winter are further important.